Method for embossed and colourless decoration and bonding of a fabric web and device therefor

ABSTRACT

A method for producing three-dimensional colourless designs in a non-woven fabric or like material entirely bonded includes subjecting the fibers to a blowing process through openings, since the fibers in the openings are only displaced therein with limited depth, and are subsequently needle bonded against a supplementary support.

The invention relates to a method for colorless plastic patterning andstrengthening of a fabric web of fibers that is not woven or knitted,i.e., of a nonwoven made up of substantially finite but also endlessfibers such as synthetic staple fibers or also natural fibers.

U.S. Pat. No. 5,115,544 discloses provision of a screen with a number ofprofile-imparting elevations against which the nonwoven to be patternedis pressed by water jets. Depending on what figures are applied aselevations on the endless screen or bent into the screen, highly variedpatterns, including perforated patterns, can be generated. The fibersare laterally displaced next to the elevations by the water jets, sothat the elevations are substantially free of fibers. A similardisclosure is provided by EP-A-0 511 025, according to which elevationson a screen likewise ensure the colorless pattern. Here, hot air canalso be employed as the medium for moving the fibers.

Further, DE-A-21 09 143 discloses moving a template with cutoutscorresponding to the desired pattern over the fabric web, against whichcutouts hot air is blown under pressure. However, this method, knownfrom the color printing process, has likewise proved unsatisfactory. Thesame is true for the idea of DE-A-20 211 188—in which the patterning iseffected by the template, likewise with hot air—that the air causesindividual fibers of the pile-like fabric web to shrink as desired forthe pattern.

In addition, reference should also be made to EP-A-0 423 619, accordingto which the fibers of a nonwoven are moved against a perforated drum bywater jets in order to move the fibers into the holes of the perforateddrum. In this way there results a nonwoven with a thin back and a frontpattern side with fibers of the nonwoven there strongly concentrated inpattern fashion. The concentration of the fibers is undefinable inparticular in the thickness of the nonwoven and the strengthening of thenonwoven is nearly equal to zero in the region of the pattern-fashionthickenings. The fibers of the nonwoven are shifted by the water jetsinto the recesses of the perforated drum in pattern fashion, but thereis no strengthening of the fibers in the recesses.

Starting from the method of the type stated at the outset, the goal isto find a method by which, without great expense, a pattern can becontinuously induced in the nonwoven or the like, which pattern isclearly defined in height as well, in which the moved fibers arelikewise mutually interlaced and thus strengthened.

In order to achieve this goal, the invention provides that the fibers ofthe fabric web lying in a first plane provided with the intended patternare partly displaced by high-energy water jets into a second plane andthere held up against further displacement by an existing resistance,the impinging liquid is drained off, and the fibers of the fabric web inthe two planes are intertwined with one another by the action of thewater jets so that the nonwoven is strengthened over its entire area andwith a pattern. Essential for clearly delimited patterning in a nonwovenuniformly strengthened over the entire area, similarly to a watermark ina paper, is the prevention of tearing of the nonwoven into two planesupon hydrodynamic needling. Strengthening should be the same everywhere,no holes of any kind should appear, and also the thickness of thenonwoven in the two planes should remain equal and invariant.

A device for carrying out the method is provided with a substratepresent in the direction of the flowing water jets, which is only partlyliquid-permeable and is open with a pattern. There, further, there is apressurized-water bar assigned to this substrate for the production offine water jets distributed over the working width. This device is nowsupplemented by a further substrate, likewise braced andliquid-permeable and provided as a supporting resistance for the fibersdisplaced by the pattern-imparting substrate, arranged beneath thepattern-imparting substrate. The device could advantageously be made upof a supporting, intrinsically stable, liquid-permeable drum such as aperforated drum, which is externally surrounded by a fine-meshedperforated belt such as a spun lace belt, and this by apattern-imparting and likewise liquid-permeable belt or foil to whichthe pressurized-water bar is radially outwardly assigned. It is furtheradvantageous to brace the spun lace belt on the perforated drum with afurther, coarser screen fabric.

A device of the type according to the invention is depicted in exemplaryfashion in the drawings, in which:

FIG. 1 shows in cross section a permeable perforated drum, held undersuction, for production of a patterned nonwoven with the nozzle baroutwardly assigned to the perforated drum, and

FIG. 2 shows the jacket of the perforated drum of FIG. 1 in enlargeddepiction, and

FIG. 3 shows the jacket of the perforated drum of FIG. 2 withsupplemented structure.

Further peripheral components are also associated with perforated drum 1visible in FIG. 1, but these are omitted here for the sake of clarity.Nonwoven 2 to be patterned runs directly over perforated drum 1, towhich one or a plurality of nozzle bars 3 are directly externallyassigned. Respective nozzle bar 3 is arranged axially parallel toperforated drum 1 and is provided, on its underside assigned toperforated drum 1, with a row of nozzles, not depicted here, for thedischarge of water jets 4. As usual, perforated drum 1 is placed undersuction for the extraction of the sprayed-on water, to which end asuction tube 8 is centrally arranged inside perforated drum 1, whichsuction tube has suction slots 10 extending to perforated drum 1, towhich slots nozzle bars 3 are in turn assigned.

According to FIG. 1, perforated drum 1 is made up of a seamlessperforated drum wall 11, which is provided as a backing element forfurther form elements slipped onto the outside. The holes of perforateddrum wall 11 can be stamped into a metal sheet or the wall can haveanother stable structure. According to FIG. 2, a fine screen fabric, aspun lace belt 12, is slipped onto the perforated drum wall, onto whichbelt a metal sheet 5 provided with a pattern of holes is slipped inturn. Holes 7 are therefore drawn with various diameters. Of course,holes 7 can also have shapes other than round; any pattern, including alarge-area pattern, is conceivable here.

If now water jets 4 impinge on nonwoven 2, which is smooth on bothsides, the fibers in the region of holes 7 move into these holes and thenonwoven is needled and strengthened on webs 9 between holes 7. Themotion of the fibers into holes 7 of thin patterned sheet 5 is limited,however, because a fine screen fabric 12 is arranged beneath patternedsheet 5, which screen fabric can be viewed as a spun lace belt initself. Normally it serves as substrate for a nonwoven to be smoothlyneedled. The sprayed-on water penetrates through belt 12 and isextracted inside perforated drum 1. The fibers, however, remain lying onbelt 12 and are also needled, i.e., strengthened, there by the waterjets. In this way a plastic pattern arises on one side in a nonwovenstrengthened over its entire area.

In FIG. 3 the structure of the perforated drum jacket is the same as inFIG. 2, but a coarser screen fabric 13 has been slipped in between spunlace belt 12 and supporting perforated drum wall 11, which coarserscreen fabric increases the spacing between the supporting perforateddrum surface and spun lace belt 12. This equalizes the water flow fromscreen belt 12 to the through-flow openings of perforated drum 11 andthe webs between the through-flow openings no longer form an obstacle tothe through flow.

1. Method for colorless plastic patterning and strengthening of anonwoven fabric web of fibers that is not woven or knitted, comprising:providing a perforated drum, a coarse-meshed screen fabric externallysurrounding the perforated drum, a fine meshed spun lace belt braced onthe perforated drum via the coarse-meshed screen fabric that isinterposed between the perforated drum and the fine meshed spun lacebelt, and a pattern-imparting substrate, which is only partlyliquid-permeable and is open with a pattern, externally surrounding thefine meshed spun lace belt; providing a nonwoven fabric web over thepattern-imparting substrate; impinging high-energy water jets against anouter surface of the nonwoven fabric web, whereby fibers of the fabricweb lying in a first plane provided with an intended pattern are partlydisplaced by impinging liquid in the high-energy water jets into asecond plane and held up in the second plane against furtherdisplacement by the fine meshed spun lace belt; and draining theimpinging liquid, whereby the fibers of the fabric web in the first andsecond planes are intertwined with one another by the action of thehigh-energy water jets so that the nonwoven fabric web is strengthenedover its entire area and with a pattern.
 2. Method according to claim 1,wherein the nonwoven fabric web comprises substantially finite fibers.3. Method according to claim 2, wherein the substantially finite fiberscomprise synthetic staple fibers.
 4. Method according to claim 2,wherein the substantially finite fibers comprise natural fibers. 5.Device for carrying out the method of claim 1, comprising a perforateddrum, a coarse-meshed screen fabric externally surrounding theperforated drum, a fine meshed spun lace belt braced on the perforateddrum via the coarse-meshed screen fabric that is interposed between theperforated drum and the fine meshed spun lace belt, a pattern-impartingsubstrate, which is only partly liquid-permeable and is open with apattern, externally surrounding the fine meshed spun lace belt, and apressurized-water bar provided adjacent to the pattern-impartingsubstrate for the production of fine water jets distributed over aworking width of the pressurized-water bar.
 6. Device according to claim5, wherein the perforated drum comprises a supporting, intrinsicallystable, liquid-permeable drum, and the pressurized-water bar is providedradially outwardly from the perforated drum.